This invention involves apparatus for folding a continuous length of of web along a longitudinal fold line and more specifically to a folder having novel features which effects folding a continuous length of web material without forming gussets or marking the web or smearing any of the printing of the printing thereon.
Mechanisms for folding a continuous length of web material along a longitudinal fold line as the web moves longitudinally are well known. Such equipment is adapted to fold the paper web material as it is passed to the cutter and sheeter. Conventional apparatus for folding such web material comprises entrance and exit rollers and between these rollers is disposed a folding plow. All of these components are mounted on a frame which may or may not be part of the press.
A particular problem that exists with well known web folders is the formation of wrinkles or gussets at the line of fold and marking of the web in the region of the fold. The problem of web marking is especially significant in web folding equipment employed in the printing industry. However, the problems of wrinkling and gussetting adversely affects the folding of substantially any web material where a sharp crease at the fold line is demanded.
A further problem which occurs in the longitudinal folding of different kinds of web material is the tendency of the folded portion of the web to unfold following the initial folding.
Prior folders have recognized the problem and have attempted to provide a solution by such means as goose neck type arm supported rollers and the like for engaging the folded web generally at the fold line. However, they have been generally found to be unsatisfactory.